Revert "Use livekit's Rust SDK instead of their swift SDK (#13343)" (#20809)

Issues found:

* audio does not work well with various set-ups using USB
* switching audio during initial join may leave the client with no audio
at all
* audio streaming is done on the main thread, beachballing certain
set-ups
* worse screenshare quality (seems that there's no dynamic scaling
anymore, compared to the Swift SDK)

This reverts commit 1235d0808e.

Release Notes:

- N/A

crates/gpui/src/app.rs

@@ -33,8 +33,8 @@ use crate::{
     Entity, EventEmitter, ForegroundExecutor, Global, KeyBinding, Keymap, Keystroke, LayoutId,
     Menu, MenuItem, OwnedMenu, PathPromptOptions, Pixels, Platform, PlatformDisplay, Point,
     PromptBuilder, PromptHandle, PromptLevel, Render, RenderablePromptHandle, Reservation,
-    ScreenCaptureSource, SharedString, SubscriberSet, Subscription, SvgRenderer, Task, TextSystem,
-    View, ViewContext, Window, WindowAppearance, WindowContext, WindowHandle, WindowId,
+    SharedString, SubscriberSet, Subscription, SvgRenderer, Task, TextSystem, View, ViewContext,
+    Window, WindowAppearance, WindowContext, WindowHandle, WindowId,
 };
 
 mod async_context;
@@ -599,13 +599,6 @@ impl AppContext {
         self.platform.primary_display()
     }
 
-    /// Returns a list of available screen capture sources.
-    pub fn screen_capture_sources(
-        &self,
-    ) -> oneshot::Receiver<Result<Vec<Box<dyn ScreenCaptureSource>>>> {
-        self.platform.screen_capture_sources()
-    }
-
     /// Returns the display with the given ID, if one exists.
     pub fn find_display(&self, id: DisplayId) -> Option<Rc<dyn PlatformDisplay>> {
         self.displays()